Your airplane's job interview: what a pre-buy inspection is really testing
Every retail airplane sale has a moment where the deal stops being about photos and phone calls and starts being about what a mechanic finds. That's the pre-buy inspection, and it's where more airplane sales fall apart than anywhere else. Think of it as your airplane's job interview: a stranger with a flashlight, a borescope, and your logbooks, trying to decide whether to recommend it to the person paying them.
I'm an A&P and a flight instructor, so I've looked at airplanes from the mechanic's side of that table and the pilot's side. Here's what the interview actually tests, how to prepare your airplane for it, and what to do when the answers aren't perfect.
First, what a pre-buy is (and isn't)
A pre-buy is an inspection the buyer orders, by a mechanic the buyer picks, to find out what they're really buying. The buyer usually pays for it. The scope is whatever the buyer and their mechanic agree on — it can be a quick look or something close to a full annual.
What it isn't: an annual, a promise to fix anything, or your mechanic's opinion. The person doing it works for the buyer. They're not out to get you, but their job is to find things, and a good one will.
Question one: do the records hold up?
A lot of pre-buys start at the kitchen table, not the hangar. Before anyone opens a cowling, the mechanic reads the logbooks looking for a few things:
- Continuity. Annuals in sequence, no unexplained gaps, total times that add up from one entry to the next.
- Airworthiness directives. A clear record of which ADs apply and how each one was complied with.
- Major repairs and alterations. The paperwork behind anything significant — a repair after damage, an avionics install, an engine change — and whether it was done and documented properly.
- The paperwork in the airplane. Registration, airworthiness certificate, and a current weight and balance with an equipment list that matches what's actually installed.
Records problems are where a lot of buyers get nervous fastest, because they can't be fixed with a wrench. If you already know your records have holes, it's worth reading how missing logbooks affect value before you list.
Question two: is the engine healthy?
The engine is usually the most expensive single thing on the airplane, so it gets the most scrutiny. Expect compression checks on every cylinder, a borescope look inside the cylinders, and a look at the oil and filter for metal. Some buyers will also send oil off for analysis. The mechanic is trying to answer one question: is this engine going to make it to its expected overhaul, or is the buyer about to inherit a cylinder job — or worse?
Question three: what's hiding in the airframe?
With inspection panels off, the mechanic is looking for the things owners don't see from the pilot's seat: corrosion, worn or frayed control cables, cracks, loose or worn hardware, signs of old damage, and leaks. On some types there are known trouble spots that every experienced mechanic checks first. They'll also run the avionics, the lights, the gear if it's retractable, and everything else with a switch.
How to prepare your airplane for its interview
You can't change what the airplane is, but you can make sure it shows up honestly and well:
- Organize the logbooks. In order, tabbed if you can, with an AD compliance list and the major repair and alteration paperwork in one place. A mechanic who can follow the history easily trusts it more.
- Fix the cheap, obvious stuff. A dead battery, a flat tire, a burned-out bulb, overdue oil. These cost little and keep a buyer from wondering what else was neglected.
- Don't start big projects. Major work right before a sale rarely pays for itself, and fresh work can raise as many questions as it answers.
- Disclose what you know. If you know about a leak, a weak cylinder, or an old repair, say so up front. A buyer who hears it from you negotiates. A buyer who finds it themselves starts wondering what else you didn't mention.
- Settle the logistics in writing. Who pays, where it happens, how long the airplane will be opened up, whether there's a test flight and who's flying, and that you get a copy of the findings.
When the findings come back
Almost every pre-buy finds something. A long list doesn't mean the airplane is bad. What matters is sorting it into two piles: items that affect airworthiness, and items that are about condition or preference. The first pile has to be dealt with somehow. The second is a conversation.
From there you have three choices: fix the items, adjust the price, or let the buyer walk. Each one costs you something — money, time, or starting over with the next buyer and their own pre-buy. That last one is the real cost of the retail route, and it's why the pre-buy is where so many sales timelines stretch from weeks into months. Our guide to selling your airplane quickly goes into what that does to your calendar, and the full retail process is laid out in how to sell a private airplane.
Skipping the interview
If the idea of a stranger's squawk list turning into weeks of back-and-forth doesn't appeal to you, there's another way. When we buy an airplane, we look at it ourselves and price it as it actually sits — records, engine, airframe, and all. You aren't handed a list of things to fix before closing, and there's no second buyer to start over with if the first one walks. The money and paperwork move through a licensed aviation title company, the same as any sale.
The short version
A pre-buy tests three things: whether the records hold up, whether the engine is healthy, and what's hiding in the airframe. Organize the books, fix the cheap stuff, disclose what you know, and treat the findings as a negotiation rather than a verdict. Or, if you'd rather know your number without the interview, ask us for a no-obligation cash offer.